Implementation
To maintain a highly available SharePoint environment, you need to ensure that
the availability options at each tier of your architecture meet your needs.
The following procedures relate to the three-tier architectural model: Web servers
in one tier, application services in another tier, and the database back end
in the third tier. To accomplish the following implementation tasks in a two-tier
environment, just add the application server services to the Web servers.
Web servers. To make Web servers highly available, you
need two or more servers. You also need to run NLB or use an external load balancer.
The first step is to install MOSS on the servers you'll be using for
the Web front end. When you begin the installation, you'll be prompted whether
you want to perform a Basic or Advanced installation. Because this won't be
a standalone installation, select Advanced, and on the next page, select Web
Front End-Only install components required to render content to users, as Figure 2 shows. Then click Install Now. When
the installation completes, click Close, which opens the SharePoint Products
and Technologies Configuration Wizard. Proceed through the wizard by performing
these steps:
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Click Next at the Welcome screen and click Yes in the dialog box that advises
that you might have to start or reset related services during configuration.
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Next, select whether you want to connect to an existing farm or start
a new one.
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Specify the configuration database server and the name of the database,
as Figure 3 shows. Then enter the credentials
for the account that the machine will use to connect to the configuration
database.
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If you want to install the Central Administration Web application on your
Web server, select that check box and note the port number (in case you
want to load balance it across your Web servers). You'll see a summary of
your choices. Confirm that they're correct and click Next. Click Finish.
After you install MOSS on your Web servers, you'll need to configure load balancing.
For this example, I show you how to set up NLB with IGMP Multicast on Windows
Server 2003. I prefer to use the Network Load Balancing Manager, which you'll
find under the Windows 2003 Administrative Tools menu. To set up NLB, perform
these steps:
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Start the Network Load Balancing Manager on any machine in the domain
and click Cluster, New.
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On the Cluster Parameters screen, enter the cluster's IP address and Subnet
mask. Under Cluster operation mode, select the Multicast option and
the IGMP Multicast check box, as Figure 4,
shows. Click Next.
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You'll be prompted to enter additional cluster IP addresses, which is
handy if you plan to host multiple Secure Sockets Layer (SSL) sites and
want them to be load balanced. Click Next.
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Next, you need to configure port rules. Using the options here, you can
specify which ports are load balanced on a per IP address basis. This means
that if you're only hosting one protocol in your NLB cluster (e.g., HTTP),
you need to open only the related ports. Click Next.
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On this screen, you specify the first host to be added to the cluster.
Enter the name of one of your Web servers and click Next. This screen shows
the configuration of the host you've selected. It contains the host priority
(which is the host ID within the cluster), the dedicated IP information
of the host, and the initial host state (the defaults is Started). Click
Finish.
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The left panel of the Network Load Balancing Manager shows your first
host along with its description and state, as Figure
5 shows.
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Click Cluster, Add Host, and enter the name of the next host you want
to join to the cluster. Click Next, then click Finish. Repeat this step
for each host you want to add.
Don't forget to add DNS records that point to
the NLB cluster IP address for the sites you're
load-balancing.
Application servers. You can run the Query service on
any number of application servers. However, the Query and Index services can't
reside on the same server. If they do, the Index service recognizes that the
Query service is installed and it won't propagate the index. If the content
you're hosting is relatively static (50 percent or more of the requests for
your Web servers are for static content), you can see a potential performance
boost by moving the Query service to your Web servers. The resulting performance
boost is due to the content caching done by the Query service.
Excel Calculation Services provides support
for server-side calculation of workbooks hosted
through Excel Web Access in MOSS 2007. A
request to process a workbook is sent to a server
running Excel Calculation Services. The service
stores session-state information so that the
same server processes the request until the user
session ends or the workbook is closed.
Excel Calculation Services is a resource-intensive service, so in large environments
with heavy utilization of complex workbooks, you might want to dedicate a couple
of high power servers solely to this service. I've worked at companies that
relied on workbooks so complex that it took a high-end, dual-core machine longer
than an hour to do the calculations on them. Cases like that let you see SharePoint's
true value. If you upload the workbook and make it accessible through Excel
Web Access, the calculations are performed from a central location, and you
need to buy only the application servers instead of buying expensive workstations
for all employees that need to view the worksheets. Keep in mind, though, that
because these operations are so resource-intensive, they might affect other
services running on the servers.
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You say: "It does no good to have redundant servers if your storage device represent a possible single point of failure".
But also you "recommend" to use NLB, which is not able to detect software level errors. Meaning, if the web site goes down for some reason, NLB still behaves like there are no problems.
Also even your storage is HA designed, you still have a Quorum disk in cluster. If you lost that the whole cluster shutdown.
Pepi August 29, 2007 (Article Rating: